Monikulmio

#include <bits/stdc++.h>

using namespace std;
using ll = long long;
using ld = long double;

#define MOD (ll)(998244353LL) // 1e9+7

int n, m, k;
vector<vector<char>> c;
vector<vector<bool>> b;
pair<int, int> dirs[4] = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cin >> n >> m >> k;
    vector<pair<int, int>> p(k);
    for (auto &x : p)
        cin >> x.first >> x.second;

    c.resize(n, vector<char>(m, '#'));
    b.resize(n, vector<bool>(m));
    vector<int> dx(k), dy(k);
    for (int i = 0; i < k; i++) {
        int x = p[i].second - 1;
        int y = p[i].first - 1;
        dy[i] = p[(i + 1) % k].first - p[i].first;
        dx[i] = p[(i + 1) % k].second - p[i].second;
        int z = max(abs(dy[i]), abs(dx[i]));
        char e;
        if (dy[i] != 0)
            dy[i] = dy[i] > 0 ? 1 : -1;
        if (dx[i] != 0)
            dx[i] = dx[i] > 0 ? 1 : -1;
        if (dy[i] == 0) {
            e = '=';
        }
        else if (dx[i] == 0) {
            e = '|';
        }
        else if (abs(dy[i] + dx[i]) == 2){
            e = '\\';
        }
        else {
            e = '/';
        }

        c[y][x] = '*';
        for (int j = 1; j < z; j++) {
            x += dx[i];
            y += dy[i];
            c[y][x] = e;
        }
    }
    priority_queue<tuple<int, int, int>> q;
    for (int x = 0; x < m; x++) {
        q.push({c[0][x] == '#' ? 0 : -1, 0, x});
        q.push({c[n-1][x] == '#' ? 0 : -1, n-1, x});
    }
    for (int y = 0; y < n; y++) {
        q.push({c[y][0] == '#' ? 0 : -1, y, 0});
        q.push({c[y][m-1] == '#' ? 0 : -1, y, m-1});
    }
    while (!q.empty()) {
        tuple<int, int, int> t = q.top();
        int v = get<0>(t), y = get<1>(t), x = get<2>(t);
        
        q.pop();
        if (b[y][x])
            continue;
        b[y][x] = true;
        if (-v % 2 == 0 && c[y][x] == '#') c[y][x] = '.';

        for (const auto &d : dirs) {
            if (y + d.first < 0 || y + d.first >= n || x + d.second < 0 || x + d.second >= m || b[y + d.first][x + d.second])
                continue;
            if ((c[y][x] != '#' && c[y][x] != '.') && (c[y + d.first][x + d.second] != '#' && c[y + d.first][x + d.second] != '.')) continue;
                int k = v;
            if ((c[y][x] == '#' || c[y][x] == '.') && (c[y + d.first][x + d.second] != '#' && c[y + d.first][x + d.second] != '.')) k--;
            q.push({k, y + d.first, x + d.second});
        }
    }
    for (int y = 0; y < n; y++)
    {
        for (int x = 0; x < m; x++)
        {
            cout << c[y][x];
        }
        cout << "\n";
    }
}

Test 1 (public)

Verdict: ACCEPTED

Test 2 (public)

Verdict: ACCEPTED

Test 3 (public)

Verdict: ACCEPTED

Test 4 (public)

Verdict: ACCEPTED

Test 5 (public)

Verdict: ACCEPTED

Test 6 (public)

Verdict: ACCEPTED

Test 7 (public)

Verdict: ACCEPTED

Test 8 (public)

Verdict: ACCEPTED

Test 9 (public)

Verdict: ACCEPTED

Test 10 (public)

Verdict: ACCEPTED